Flat cables made in the form of a plastic film with a number of parallel conductive film strips or flexible circuits (generally referred to below as flat cables) are widely used for connecting the conductive pads of printed circuit boards or for forming connections between such conductive pads and the contacts of electronic components. Due to their light weight, flat cables are used practically in every kind of home and other electronic equipment.
In order to improve the serviceability of the electronic equipment, the connections between the circuit boards and electronic components are usually made by means of flat cables, and since the compactness is an important feature of the electronic equipment, it is necessary to make the connectors as compact as possible.
A number of types of connectors for flat cables have been proposed and implemented. For example, in vertical type connectors for flat cables according to Japanese Utility Model Publication No. 1991-22869 and Japanese Patent Publication No. 1992-65504 a number of tuning-fork-shaped contacts are secured in the housing. One end of the flat cable, together with an insulating slider, is inserted between the tuning-fork-shaped contacts. The slider is used to properly (without bending) guide very thin and flexible cable between the contacts. It also provides for a proper alignment of the conductive film strips of the flat cable and the contact points of the contacts, as well as for a better resistance to the pulling forces, thus resulting in more reliable electrical connections.
In order to obtain a high density low-profile design, horizontal-type connectors for flat cables were proposed in Japanese Utility Model Publication No. 1991-266384 and Japanese Utility Model Publication No. 1990-120780 with elastic tuning-fork-shaped or triangular contacts.
In order to obtain proper insertion of flat cables in the conventional connectors for flat cables mentioned above and in order to obtain a reliable electrical connection by applying a certain pull-out force, it is necessary to use a slider. In other words, the connector must have at least three components (housing, contacts and slider), thus making it difficult to obtain compact and inexpensive connectors for flat cables.
Attempts to avoid the use of a slider in conventional connectors for flat cables has been made; for example, connectors proposed in Japanese Utility Model Publication No. 1991-33983. In this comparatively low-cost connector for flat cables, a free end of the contacts in the form of a cantilevered bridge has a sharp edge. However, it is difficult to design contacts that would provide both for a rather low force required for insertion of the flat cable and for sufficient resistance to the pull-out efforts. Contacts with a sharp edge develop some resistance to pull-out efforts, but when the flat cable is pulled out, they leave scratches on the conductive film strips of the flat cable. Because of this, connectors of such a design are not suitable for applications requiring repetitive insertions and removals of the flat cable from the connector.
One of the ways to solve the above problems consists in providing ample access space for the flat cable to accommodate a rotating insulating cover pressing on the cantilevered bridge type contact during insertion in or removal of the flat cable from the connector. Examples of such a solution are disclosed in U.S. Pat. Nos. 4,944,690 and 4,936,792. Use of a hinged or pivoted cover is very effective whereby neither cable nor contacts become damaged and the cable insertion requires only low or no effort, while providing for a reliable electrical connection between the conductive film strips of the flat cable and the contacts of the connector.
On the other hand, such a rotating cover represents a disadvantage because it makes the manufacturing of connectors for flat cables more difficult and cost-extensive. Another disadvantage consists in the fact that the design and operation of the connectors with rotating cover are complicated, because the cover should be positively fixed and difficult to open.
Therefore, the purpose of this invention is to offer a connector for flat cables which consists basically of two parts and is easy in manufacturing and use.